level 48 solution :
read the rules and translate them :
Blue and Green is bigger than Red
Green is bigger than Blue
so the order is Green Blue Red

using the 3xR 2xG and 1xB get these balls :
green ball to inventory and put it on the path, then turn your phone or device upside down
so the ball moves into the hole
do it again one more time for the green
change into blue 1x then last 3x for red to open the door